1. Field of the Invention
The present invention relates to the structure and layout of a small, thin magnetic disk drive device used as an external memory device for a computer.
The present invention also relates to a parking drive mechanism for a magnetic head which, when a magnetic disk drive device is halted, utilizes the counter electromotive voltage from a disk rotary drive member (spindle motor) to drive a magnetic head drive member and move the magnetic head to a parking position.
2. Description of the Prior Art
A non-contact type magnetic head, generally, a floating magnetic head, is normally used in a magnetic disk drive device to avoid damage to the magnetic disk, which is the recording medium. This magnetic head, for example, is mounted on a flexure on which an actuator can swing, and from the balance between the pressure of the flexure which energizes the magnetic head to the surface of the magnetic disk and the floating force from the airflow produced by the rotation of the magnetic disk, a minute amount of floating is obtained. This type of magnetic disk drive device is generally driven by a contact start/stop system (CSS), in which system, the magnetic disk and the magnetic head remain in contact with each other either when the magnetic disk drive device is started or when the device is halted. With this system, the magnetic head on standby is normally in contact with the magnetic disk. When the device is started, the magnetic disk rotates and the airflow accompanying this rotation causes the magnetic head to float up from the surface of the magnetic disk, and drives it to access the disk for recording or read-out of data, and when the device is halted the magnetic head comes to rest at that point, and is maintained in contact with the magnetic disk. However, with this type of system, there is the problem of damage to the magnetic head or magnetic disk at the memory section of the magnetic disk, caused by the magnetic head coming to rest after floating. In addition, when contact is maintained over a long interval, there is the problem that the magnetic head adheres to the magnetic disk so that it cannot start. Further, the actuator when not in use can swing during transportation or from some external force, causing problems from the clashing of the magnetic head and magnetic disk.
Accordingly, in Japanese Laid-Open Patent Application 60-38773 a configuration was proposed in which the magnetic head does not contact the magnetic disk during a stoppage in operation, preventing adherence of the magnetic head to the magnetic disk when the device is not in use.
However, even with this system damage to both the magnetic head and the magnetic disk from impact cannot be avoided.
In Japanese Patent Publication 63-15671, it has been proposed that the actuator be driven by utilizing the counter electromotive force from a spindle motor when a power outage occurs. The magnetic head comes to rest at a non-memory section of the magnetic disk and is locked at that position so that the actuator is secured in an immovable state. On starting up, by freeing the actuator the magnetic head can be moved to a resting position with good efficiency by shutting off the power, and locked at that position so that damage to the magnetic head and the magnetic disk from the swings of the actuator during transportation or from some external force is prevented.
However, in a conventional parking transfer system using a spindle motor, because the counter electromotive voltage from the rotation of the spindle motor when the system is halted is directly applied to a voice coil motor (magnetic head drive device), excess current flows to the voice coil motor, and the actuator which supports the magnetic head moves at high speed so that the stopper is subjected to excessive impact. This causes the problem that the magnetic head damages the magnetic disk, or bounces back so that it cannot either come to rest or be locked in a normal position.
As a countermeasure, an attempt was made to increase the cushioning using a stopper made from a more flexible, high grade rubber material, but the cost was increased and the necessity for precise positioning was produced which led to unstable quality. Furthermore, no countermeasure was taken to prevent the adhesion of the magnetic head to the magnetic disk.
In addition, the system by which the magnetic head is raised and parked at the outer side of the magnetic disk during the halt in operation is also known. However, with this system, for some reason, when the parking mechanism is not operated skillfully, the magnetic head falls off the magnetic disk, causing a major problem. Also, because it frequently happens that important data has been written into the outer peripheral section of the magnetic disk, if an error occurs during the parking operation important data is destroyed and there is concern that this could lead to a non-recoverable condition. Furthermore, in order to move the head to the outside of the magnetic disk, the range of movement of the magnetic head must be large, requiring a large voice coil motor, leading to the problem that it is difficult to make an over-all compact device.
A device for parking the magnetic head on the outer peripheral section of the magnetic disk in this manner is marketed by the PrairieTek Corporation (US) as its Model 220A.
In addition, other than the above, automatic parking mechanisms have been disclosed in U.S. Pat. No. 4,562,500, U.S. Pat. No. 4,654,735, U.S. Pat. No. 4,755,982, Japanese Patent Publication 63-55154, Japanese Utility Model Publication 56-35984, Japanese Laid-Open Patent Application 58-45670, Japanese Laid-Open Patent Application 60-133577, Japanese Laid-Open Patent Application 60-147980, Japanese Laid-Open Patent Application 61-77174, Japanese Laid-Open Patent Application 61-269275, and Japanese Laid-Open Patent Application 61-287084; lock mechanisms have been disclosed in Japanese Patent Publication 63-48110, Japanese Laid-Open Patent Application 60-29981, Japanese Laid-Open Patent Application 60-106080, Japanese Laid-Open Patent Application 60-133576, Japanese Laid-Open Patent Application 60-147981, Japanese Laid-Open Patent Application 60-193180, and Japanese Laid-Open Patent Application 60-197984; lifters have been disclosed in U.S. Pat. No. 4,742,410 and Japanese Laid-Open Utility Model Application 61-158668, and the utilization of the counter electromotive force of a spindle motor in Japanese Laid-Open Patent Application 62-219274. However, none of these references discloses the device of the present invention.
In addition, a magnetic disk drive device is known, for example, in which a magnetic disk is caused to rotate, an actuator is driven by a voice coil motor, a magnetic head is caused to move in the radial direction to access the magnetic disk, and a read or a write signal is transmitted to the magnetic head so that data is read out or recorded.
Accordingly, it is necessary to have an interchange of read/write signals between an external drive circuit and the magnetic head, and to feed to a voice coil the drive current from a voice coil motor. For this reason, a flexible printed circuit substrate (FPC) is conventionally used, and the external circuit and the inside of the housing are electrically connected.
FIG. 27 is an explanatory figure showing the pull-out structure of a conventional FPC 81. The FPC 81, which is drawn out so that a side wall section 25a of a housing base 25 is ridden up, is electrically connected to a connector 151 which is provided on a drive printed circuit board (hereinafter referred to as a PCB) 13. A housing cover (omitted from the figure) is set over the housing base 25 to keep the entire device airtight via a gasket.
However, in the above structure the operation of connecting the FPC 81 and the connector 151 is poor, and is only possible manually and cannot be handled automatically. Also, the positioning of the FPC 81 is difficult and it is necessary to temporarily secure the FPC 81 with an adhesive tape to position it. Also, there is the problem that the FPC 81, when in a free state prior to being connected to the connector 151, is highly unstable and gets tangled up and broken, or the like, and is easily damaged.
In Japanese Laid-Open Utility Model Application 64-24592, a disclosure is made of a groove, formed at a position where the FPC 81 passes, which is located at the outer peripheral side surface of the sidewall section 25a of the housing base 25, and has a depth and width greater than the thickness and width of the FPC 81.
However, with this structure also, the above-mentioned problems basically cannot be eliminated.
Further, as shown in FIG. 28, a plurality of through holes is provided in a bottom plate 25b of the housing base 25, the pins of a pin header 153 are inserted into these through holes, and an adhesive 155 is filled into a space between the pin header 153 and the bottom plate 25b of the housing base 25. A socket 161 is mounted on the FPC 81 which is connected to the inside of the housing through a plurality of pins 157 inserted into the socket 161. A socket 163 is also mounted on the PCB 13 and the pins of the pin header 153 are inserted.
However, with this construction, because airtightness is required in securing the pin header 153, an operation for filling the adhesive 155 is required, and an air tightness test is also necessary, In addition, position precision is necessary to secure the pin header 153, and this positioning is difficult. This causes problems with operability and automation. In addition, two sockets (161 and 163) are necessary, and because the pin header 153 has a special shape, common parts cannot be used so the cost is increased.